Mitre angles

[ianb1965]

This is hurting my head.

Wife wants those frame things on the staircase wall I think it’s called Wainscoating. The top and bottom follow the slope of the stairs. So I’ve worked out that two of the angles are 42 degrees and two are 138. But I can’t work out what the mitre angles should be to join them together. For the 42 degrees I though two 21 degree cuts would work but no. Trigonometry was never my strong point. Any help appreciated. Hopefully attached picture shows what I mean - I’m trying to work out the angle of the white joint.

Thanks all.

 

[ianb1965]

It’s ok -sorted - need to subtract 42 from 180 = 138 and divide by 2 = too big for mitre saw!

 

[Deleted member 174758]

Set up a false fence for your mitre saw with a 45° angle. That way you'll be able to cut those acute angles

 

[EddieM]

Isn't it just 21° t'other way?

 

[ianb1965]

Thanks for your replies guys. JobAndKnock - yep just been watching a YouTube on that. Eddie - I think so but won’t that mean putting the short side of the wood against the fence so lengthwise it will be sticking out in front of the saw?

 

[oldbutnotdead]

Or use a straight edge and a router with a bearing cutter or a guide bush to do the final cuts (with the extra 45 degree fence your mitre saw may not have enough travel to make the full cut)